A gasoline direct injection engine was set-up to operate with a dynamometer in a test cell. Test cycle and emissions measurement procedures were developed for evaluating the regulated and non-regulated gaseous emissions. Equipment and techniques for particulate matter measurements were adapted for use with the gasoline direct injection engine. The particulate matter emissions produced by the engine were compared between two different fuels; gasoline and E10 (10% ethanol and 90% gasoline). The gaseous emissions generated by the engine when it was run on gasoline and E30 (30% ethanol and 70% gasoline) were also compared. Particle number decreased with E10 for hot start conditions, while the opposite was observed for cold start conditions. Particulate matter emissions were found to track with acetylene and ethylene emissions.

No description available.

No description available.

The aims and objectives: The aims and objectives of this study were to characterize and compare the airborne particulate matter in the tankhouse and crusher areas of a base metal refinery sampled with two separate methods, in terms of mass concentration, nickel content, and particle size distribution. Methods: Area sampling was conducted in the two areas. Two methods were applied to collect particulate samples. The first is a multi–stage virtual impactor, the Respicon, which was used to determine the three critical particle fractions (inhalable, thoracic and respirable). The NIOSH 7300 method determined the particle concentration and nickel percentage present in each fraction. Using formulas provided by the manufacturers two additional particle–size fractions (extra–thoracic and trachea–bronchial) could be calculated. The second was based on the standard NIOSH 0500 method, which determined particle size distribution depicted as cumulative percentages. The samples were analyzed using laser scattering instrumentation. Results: In the tankhouse the highest level of exposure was to particles bigger than 10 um, with the highest nickel percentage also falling into this range. However, high nickel percentages were present in all three cut–off sizes (4 um, 10 um and > 10 um). The particle concentration for the crusher area was the highest for particulates bigger than 10 um, with the highest nickel percentage present in this fraction. After comparing the tankhouse and crusher areas, it is clear that the particle concentration is much higher in the crusher area according to all sampling methods used. The nickel content present in the analysis of these areas is of great concern. Conclusion: With the knowledge obtained through this research one hopes to establish a basis for particle size sampling in the platinum mining industry. This may lead to the development of health based OEL's and reflect a more accurate evaluation of workers particulate exposure. This information will give a greater understanding of health risks workers are exposed to. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2011.

Background: Workers are daily exposed to diesel exhaust (DE) and DPM due to the continuous increase of diesel–powered vehicles in the underground mining environment. The National Institute for Occupational Safety and Health (NIOSH) recommends that DE be regarded as a “potential occupational carcinogen”. A great concern in the South African mining industry is that there is currently no existing occupational exposure limits (OEL) for DPM. Aim: To quantify the exposure of workers to DPM (that consists out of total carbon (TC): which is a combination of elemental carbon (EC) and organic carbon (OC)) in the ambient air of underground working environments. Also to compare different occupations exposure levels to an international standard (the Mine Safety and Health Administration’s (MSHA) OEL for TC) as South Africa has no proposed guideline or standard for occupational exposure to DPM and finally to determine whether or not occupations working at mines with different mining methods have different exposure levels to DPM. Methodology: Workers personal exposure to DPM was monitored using the NIOSH 5040 method. A DPM sampler that consisted of a cyclone, a pre–packed SKC filter cassette (37 mm) with impactor, tubing, label clips and a sampling pump was used. The flow rate was calibrated at 2.0 litres per minute (L/min) for the sampling of sub–micrometer particles. The personal sampler device was attached to the employee’s breathing zone for the duration of the work shift (normal eight–hour time–weighted average (TWA) standard). A high risk group (workers operating diesel–powered vehicles), a low risk group (workers working in the same mine, sharing the same supplied air, but not operating these vehicles) and a control group (workers working at a different mine with a different mining method) was monitored. The exposure levels were evaluated and compared with the specific OEL mentioned previously. Results: For the purpose of this study, TC exposure results were evaluated and not EC or OC. All the occupations within their specific exposure group was exposed to TC. When the control group’s exposures were compared with the high and low risk group exposures, a significant difference was recorded (p–value = 0.0001). However when the high and low risk exposures were compared with each other, no difference was recorded (p–value = 0.4405). When the results of the various groups were compared with the MSHA OEL all the occupations from the high and low risk group’s results were above the OEL, but only one occupation from the control group exceeded the OEL. Conclusion: It should be noted that all the occupations no matter the mining method / mine was exposed to TC. The high and low risk exposure groups was however much higher than the control group and a continues monitoring programme should be implemented for these exposure groups. Their results exceeded the OEL, where the control group had much lower exposure levels and only one occupation exceeded the OEL. Greater focus should be given to the mechanized mining occupations since diesel–powered vehicles are used to perform their core mining needs whereas at the conventional mine the use of these vehicles are limited. Recommendation: Depending on the different occupations sampled various engineering controls can be considered. Some include diesel oxidation catalysts (DOC), diesel particulate filters (DPF) and diesel disposable exhaust filters (DEF) or also known as disposable diesel exhaust filters (DDEF) which is very effective in removing DPM from the exhaust of dieselpowered equipment. Education and training are also critical components to the success of a diesel emission management programme and the last resort to be considered is the appropriate personal protective equipment (PPE). South Africa should consider the implementation of national standards in order to monitor the progress and success of the diesel emission management programme implemented. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2012.

The aims and objectives: The aims and objectives of this study were to characterize and compare the airborne particulate matter in the tankhouse and crusher areas of a base metal refinery sampled with two separate methods, in terms of mass concentration, nickel content, and particle size distribution. Methods: Area sampling was conducted in the two areas. Two methods were applied to collect particulate samples. The first is a multi–stage virtual impactor, the Respicon, which was used to determine the three critical particle fractions (inhalable, thoracic and respirable). The NIOSH 7300 method determined the particle concentration and nickel percentage present in each fraction. Using formulas provided by the manufacturers two additional particle–size fractions (extra–thoracic and trachea–bronchial) could be calculated. The second was based on the standard NIOSH 0500 method, which determined particle size distribution depicted as cumulative percentages. The samples were analyzed using laser scattering instrumentation. Results: In the tankhouse the highest level of exposure was to particles bigger than 10 um, with the highest nickel percentage also falling into this range. However, high nickel percentages were present in all three cut–off sizes (4 um, 10 um and > 10 um). The particle concentration for the crusher area was the highest for particulates bigger than 10 um, with the highest nickel percentage present in this fraction. After comparing the tankhouse and crusher areas, it is clear that the particle concentration is much higher in the crusher area according to all sampling methods used. The nickel content present in the analysis of these areas is of great concern. Conclusion: With the knowledge obtained through this research one hopes to establish a basis for particle size sampling in the platinum mining industry. This may lead to the development of health based OEL's and reflect a more accurate evaluation of workers particulate exposure. This information will give a greater understanding of health risks workers are exposed to. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2011.

Background: Workers are daily exposed to diesel exhaust (DE) and DPM due to the continuous increase of diesel–powered vehicles in the underground mining environment. The National Institute for Occupational Safety and Health (NIOSH) recommends that DE be regarded as a “potential occupational carcinogen”. A great concern in the South African mining industry is that there is currently no existing occupational exposure limits (OEL) for DPM. Aim: To quantify the exposure of workers to DPM (that consists out of total carbon (TC): which is a combination of elemental carbon (EC) and organic carbon (OC)) in the ambient air of underground working environments. Also to compare different occupations exposure levels to an international standard (the Mine Safety and Health Administration’s (MSHA) OEL for TC) as South Africa has no proposed guideline or standard for occupational exposure to DPM and finally to determine whether or not occupations working at mines with different mining methods have different exposure levels to DPM. Methodology: Workers personal exposure to DPM was monitored using the NIOSH 5040 method. A DPM sampler that consisted of a cyclone, a pre–packed SKC filter cassette (37 mm) with impactor, tubing, label clips and a sampling pump was used. The flow rate was calibrated at 2.0 litres per minute (L/min) for the sampling of sub–micrometer particles. The personal sampler device was attached to the employee’s breathing zone for the duration of the work shift (normal eight–hour time–weighted average (TWA) standard). A high risk group (workers operating diesel–powered vehicles), a low risk group (workers working in the same mine, sharing the same supplied air, but not operating these vehicles) and a control group (workers working at a different mine with a different mining method) was monitored. The exposure levels were evaluated and compared with the specific OEL mentioned previously. Results: For the purpose of this study, TC exposure results were evaluated and not EC or OC. All the occupations within their specific exposure group was exposed to TC. When the control group’s exposures were compared with the high and low risk group exposures, a significant difference was recorded (p–value = 0.0001). However when the high and low risk exposures were compared with each other, no difference was recorded (p–value = 0.4405). When the results of the various groups were compared with the MSHA OEL all the occupations from the high and low risk group’s results were above the OEL, but only one occupation from the control group exceeded the OEL. Conclusion: It should be noted that all the occupations no matter the mining method / mine was exposed to TC. The high and low risk exposure groups was however much higher than the control group and a continues monitoring programme should be implemented for these exposure groups. Their results exceeded the OEL, where the control group had much lower exposure levels and only one occupation exceeded the OEL. Greater focus should be given to the mechanized mining occupations since diesel–powered vehicles are used to perform their core mining needs whereas at the conventional mine the use of these vehicles are limited. Recommendation: Depending on the different occupations sampled various engineering controls can be considered. Some include diesel oxidation catalysts (DOC), diesel particulate filters (DPF) and diesel disposable exhaust filters (DEF) or also known as disposable diesel exhaust filters (DDEF) which is very effective in removing DPM from the exhaust of dieselpowered equipment. Education and training are also critical components to the success of a diesel emission management programme and the last resort to be considered is the appropriate personal protective equipment (PPE). South Africa should consider the implementation of national standards in order to monitor the progress and success of the diesel emission management programme implemented. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2012.

The goal of this thesis was to detail spatial and temporal organic particulate dynamics at an integrated multi-trophic aquaculture (IMTA) site on the west coast of Vancouver Island, Canada. To accomplish this goal, in-situ optical measurements of particulate scattering (bp), particulate backscattering (bbp) and the particulate backscattering ratio (bbp:bp) were collected in conjunction with discrete sampling for particulate organic carbon (POC) and chlorophyll a (chl a) concentrations. These measurements were performed over three seasons (autumn, winter and summer) at reference sites and at sites within and directly adjacent to the fish component of the IMTA system. Chapter 2 of this thesis focused on the examination of bio-optical relationships over various timescales (seasonally, daily and within-day) to describe temporal and vertical particulate variability and to assess the effectiveness of bio-optical methods for environmental monitoring. Autumn showed low bio-optical magnitudes with distinct lower cage increases possibly attributable to aquaculture derived wastes. In spring, sampling was performed over diatom bloom conditions, dominating the bio-optical measurements. During summer, an Emiliania Huxleyi bloom likely occurred, strongly enhancing bbp and bbp:bp magnitudes in the thermally stratified upper water column. Throughout these conditions, bp was predominantly influenced by chl a suggesting sensitivity to phytoplankton concentrations. While bbp was conditioned by chl a during the diatom bloom, it was also highly sensitive to the presence of inorganic and likely detrital materials. Finally, bbp:bp was sensitive to particulate compositions, showing low values (< 0.010) in diatom dominated waters and high values when refractive coccoliths were likely present. Notably, in autumn, bbp:bp was conditioned by detrital particles and along with bbp, showed post-feeding lower cage increases suggesting that these parameters could be useful candidates for particulate waste tracking during low ambient particle conditions. In chapter 3, the temporal, vertical and horizontal dispersion of the aquaculture derived particulate wastes are detailed. Autumn was the only period to show waste signals, likely due to their quick dilution into the particulate rich fields in spring/summer. During this period, post-feeding particulate waste increases were focused at the bottom of the cage with possible vertical sinking towards the seafloor. Minimal horizontal dispersion towards the scallop portion of the system was observed; however, more comprehensive sampling over differing hydrographic regimes is necessary to characterize waste dispersion. Based on our temporally limited autumn results, the most appropriate placement of uptake species for waste assimilation would be directly below the studied cage. Our results highlight the need for high spatial and temporal resolution methods for particulate monitoring within IMTA settings as discrete sampling may miss “patchy” waste dispersal streams. The bio-optical measurements performed during this study could fill this need as they can provide high resolution information on particulate concentrations and compositions not achievable solely through the use of discrete water sampling. With further research, optical instrumentation could be incorporated into IMTA systems allowing for the near real time and continuous collection of data on particulate dynamics. This knowledge could greatly aid in the design and implementation of systems optimized for waste removal by uptake species. / Graduate / 0792 / 0768 / 0752 / jdelbel@uvic.ca

Mechanistic aspects of carbonaceous aerosol toxicity were examined with respect to the ability of particles to catalyse reactive oxygen species-generating redox cycling reactions. To investigate the role of secondary organic material, we examined two systems. In the first, two-stroke engine exhaust particles were found to increase their ability to catalyse redox cycling in the presence of a reducing agent, dithiothreitol (DTT), when the exhaust was exposed to ozone. This occurred through deposition of redox-active secondary organic aerosol (SOA) onto the particle that was ten times more redox active per microgram than the primary engine particle. In the second system, naphthalene SOA formed highly redox active particles. Activity was strongly correlated to the amount of the 1,4- and 1,2-naphthoquinone measured in the particle phase. However, these species and the newly quantified naphthalene oxidation product 5-hydroxy-1,4-naphthoquinone accounted for only 30% of the observed DTT decay from the particles. Gas-particle partitioning coefficients suggest 1,4- and 1,2-naphthoquinone are not strong contributors to ambient particle redox activity at 25°C. However, a large number of redox active species are unidentified. Some of these may be highly oxidised products of sufficiently low vapour pressure to be atmospherically relevant. DTT activity of diesel particles was found to be high per unit mass. The activity was found to be associated with the insoluble fraction as filtration of the particles nearly eliminated DTT decay. Neither methanol nor dichloromethane extracts of diesel particles exhibited redox activity, indicating that the redox active species are associated with the black carbon portion of the particles. Examination of particle concentration techniques found that use of water condensation to grow and concentrate particles introduced a large organic artefact to the particles. Experiments with concentrated inorganic particles suggest that the source of this artefact is from irreversible uptake of water-soluble volatile organic compounds. Overall, carbonaceous redox active species can be thought of as a continuum from small, water-soluble species to redox active functionalities on elemental carbon backbones. In addition to clearly defined, quantifiable species, future research may need to consider examining broader chemical classes or redox-active chemical functionalities to overcome the inherent complexity of these constituents.

Mechanistic aspects of carbonaceous aerosol toxicity were examined with respect to the ability of particles to catalyse reactive oxygen species-generating redox cycling reactions. To investigate the role of secondary organic material, we examined two systems. In the first, two-stroke engine exhaust particles were found to increase their ability to catalyse redox cycling in the presence of a reducing agent, dithiothreitol (DTT), when the exhaust was exposed to ozone. This occurred through deposition of redox-active secondary organic aerosol (SOA) onto the particle that was ten times more redox active per microgram than the primary engine particle. In the second system, naphthalene SOA formed highly redox active particles. Activity was strongly correlated to the amount of the 1,4- and 1,2-naphthoquinone measured in the particle phase. However, these species and the newly quantified naphthalene oxidation product 5-hydroxy-1,4-naphthoquinone accounted for only 30% of the observed DTT decay from the particles. Gas-particle partitioning coefficients suggest 1,4- and 1,2-naphthoquinone are not strong contributors to ambient particle redox activity at 25°C. However, a large number of redox active species are unidentified. Some of these may be highly oxidised products of sufficiently low vapour pressure to be atmospherically relevant. DTT activity of diesel particles was found to be high per unit mass. The activity was found to be associated with the insoluble fraction as filtration of the particles nearly eliminated DTT decay. Neither methanol nor dichloromethane extracts of diesel particles exhibited redox activity, indicating that the redox active species are associated with the black carbon portion of the particles. Examination of particle concentration techniques found that use of water condensation to grow and concentrate particles introduced a large organic artefact to the particles. Experiments with concentrated inorganic particles suggest that the source of this artefact is from irreversible uptake of water-soluble volatile organic compounds. Overall, carbonaceous redox active species can be thought of as a continuum from small, water-soluble species to redox active functionalities on elemental carbon backbones. In addition to clearly defined, quantifiable species, future research may need to consider examining broader chemical classes or redox-active chemical functionalities to overcome the inherent complexity of these constituents.